1. Field of the Invention
The present invention relates to a process for producing an ink-jet recording head which is mounted on an ink-jet recording apparatus and discharges droplets of a recording liquid toward a recording medium.
2. Related Background Art
As the means for performing recording on a recording medium such as paper sheets, an ink-jet recording apparatus equipped with an ink-jet recording head is widely used in apparatuses such as calculators, word processors, facsimile machines, copying machines, and printers, because the ink-jet recording apparatus can perform high speed recording without noise, and color image recording with ease.
In the conventional processes for producing an ink-jet recording head, for example, in the process disclosed in JP-A-62-253457, an ink-jet recording head is produced by forming a solid layer at an intended position for forming a liquid path on a supporting member, laminating thereon an activation energy ray-curable material layer and a second supporting member, irradiating the region except an intended position for forming a liquid chamber with an activation energy ray, removing the activation energy ray-curable material uncured at the intended position for forming the liquid chamber to thereby form the liquid chamber, and removing the solid layer formed at the intended position for forming the liquid path to thereby form the liquid path.
However, the above production process has the following problems:
1. The material for constructing the wall of the liquid path is limited to activation energy ray-curable materials capable of being patterned to form the liquid chamber, which severely restricts the choice of materials available. PA1 2. When a common liquid chamber with larger height is formed so as to obtain intended ink droplet discharge performance of the ink-jet recording head, a larger thickness of the activation energy ray-curable material layer is required, which lowers yield due to lowering of patterning accuracy in patterning of the liquid chamber, and an expensive aligner is used for a long time enough to obtain a sufficient exposure amount to thereby raise the production cost. PA1 (1) The step for forming the second solid layer 3 is required. PA1 (2) The material for the second solid layer 3 is limited by many conditions that the material does not form an unnecessary product by reaction with the first solid layer 2, the material is incompatible with the curable resin 8, the material can be formed relatively thick (several ten microns or more), the material has high moldability, the second solid layer 3 can desirably be removed with the same removing liquid as used for removing the first solid layer 2, and so forth. PA1 (3) A solid for filling the gap such as, filler material 7 must satisfy conditions, such as (i) the filler material has flowability to fill the gap 6 but does not spread out from the solid layer 3, (ii) the filler material is removable after the resin is injected and cured, (iii) the filler material does not retard the cure of the resin by mixing, (iv) the filler material has sufficient workability, and so forth. PA1 1. An ink-jet recording head with high reliability is produced according to simple steps without using a mold material for forming the common liquid chamber, and without operation of filling the gap caused by use of the molding material. PA1 2. An inexpensive ink-jet recording head with high precision is produced because the steps of light exposure and development of the curable resin are not necessary. PA1 3. An ink-jet recording head having high reliability excellent in ink resistance, heat resistance and the like is produced because the curable resin can be selected irrespectively of the viscosity, wettability, and the like of the curable resin. PA1 4. An ink-jet recording head having high-speed response characteristic is produced at a high yield without impairing ink-refilling properties and without closing the liquid path by dusts due to exfoliated extremely thin portion of the curable resin, because extremely thin portion of the curable resin is not formed. PA1 5. An ink-jet recording head having high reliability without lowering the life of the element for generating a discharging pressure and trouble of the head due to corrosion by eluting an ink of a corrosive material is produced when a substrate made of a corrosive metal such as aluminum or the like is used as the second supporting member, because the inner wall of the opening portion in the second supporting member can be covered with the cured resin. PA1 6. An inexpensive ink-jet recording head is produced according to simple steps because the additional step of filling the opening portion with the resin to close the opening portion is not required by injecting the resin from the opening portion. Further, since the distance from the injection opening (opening portion) of the curable resin to an outlet is short, the curable resin can be easily injected into a long head such as a multi-array type head having a long size in a direction of arranging nozzles and an ink-jet recording head with high quality without mixing bubbles into the resin can be produced in a high yield.
The following process has been proposed in light of the above problems.
FIGS. 5A, 5B and 6A to 6G are perspective or sectional views for explaining a conventional process for producing an ink-jet recording head. In the process, as shown in FIG. 5A, a plurality of objects 11 to be separated later to thereby obtain opposed heads (hereinafter, opposed heads 11) are formed on a supporting member 1. Then, as shown in FIG. 5B, the opposed heads 11 are separated along cutting plane lines 12 to obtain individual heads. FIGS. 6A to 6G show production steps in sectional views taken along the line A--A in FIG. 5A.
As shown in FIG. 6A, firstly, a first solid layer 2 for forming a liquid path and a part of a liquid chamber is formed selectively by patterning or the like at the intended positions for forming the liquid path and the liquid chamber on a supporting member 1 provided with a discharge pressure-generating element 14.
As shown in FIG. 6B, a second solid layer 3 is formed at least at an intended position for forming the liquid chamber on the first solid layer 2 by printing or the like in order to obtain a sufficient volume of the liquid chamber and to obtain the gap between the supporting member 1 and a second supporting member 5 mentioned later.
As shown in FIG. 6C, a second supporting member 5 having a hole 4 for forming an ink supply opening later is placed on the second solid layer 3. Here, one opening end of the hole 4 provided in the second supporting member is closed by the second solid layer 3.
As shown in FIG. 6D, when the second supporting member 5 is placed on the second solid layer 3, small gaps 6 may exist at contacting portions between the second solid layer 3 and the second supporting member 5 owing to warpage or waving of the first supporting member 1 and the second supporting member 5, or owing to insufficient flatness or nonuniform thickness of the second solid layer 3. A curable resin 8 for forming the walls of the liquid path and liquid chamber will penetrate into the small gaps 6 by capillarity in the later step of injection of the curable resin 8. When the curable resin 8 penetrates into the gap 6, the curable resin 8 penetrated into the gap 6 becomes an extremely thin film. This thin curable resin film comes to be swollen by a removing liquid in the step of removing the first solid layer 2 and the second solid layer 3, or by an ink and then tends to exfoliate as dusts from the second supporting member 5 which clog the nozzles, or tends to remain in the form of a burr around an ink supply opening 4 to impair significantly ink refilling properties, disadvantageously. In an extreme case, the curable resin 8 spreads over the upper face of the second solid layer 3, and prevents removal of the second solid layer 3.
To solve the above problems, a flowable material 7 is filled into the gap between the second supporting member 5 and the second solid layer 3 prior to injection of the curable resin 8 for forming the wall of the liquid path.
As shown in FIG. 6E, the curable resin 8 for forming the walls of the liquid path and the liquid chamber is injected from an injection opening (not shown) between the first supporting member 1 and the second supporting member 5.
As shown in FIG. 6F, after curing the curable resin 8, the filler material 7 is removed, and the opposed heads is cut at the middle into two heads.
Finally, as shown in FIG. 6G, the first solid layer 2 and the second solid layer 3 are removed to obtain a head having a discharging portion (orifice) 9, a liquid path and a liquid chamber 10.
However, the above process has still problems as below: